Steerable locking catheter

ABSTRACT

The steerable catheter invention facilitates the tracking and selection of branch vessels, as well as provide the means for stiffening the catheter body across the tortuosity to anchor the catheter and minimize the potential for the catheter backing out of position while delivering interventional devices to the distal anatomy.

FIELD OF INVENTION

The present invention generally relates to medical instruments, and moreparticularly, to a steerable locking catheter system.

BACKGROUND

Catheters can be pliable tubular structures that enter vasculature of apatient. Catheters can be used for a variety of purposes andapplications. For example, they can be introduced into a particular areaof interest within a vasculature and then act as a guide for introducingother peripheral, central venous, or arterial devices therein throughits lumen. Such devices can include single or multi-lumen catheters,clot capturing devices, balloon catheters, and the like.

Tracking of catheters through tortuous anatomy can be challenging,especially for larger diameter catheters. These catheters are difficultto track in the presence of tortuosity and selecting branch vesselsmakes it more difficult. In addition, once the catheter is trackedthrough tortuous vasculature, and an interventional device (such as astent, clot retriever, aspiration catheter, etc.) is advanced throughthe lumen of the catheter, it often results in the catheter backing outof position. If this occurs, the physician must remove theinterventional device and then re-access the tortuous segment with thecatheter prior to re-attempting delivery of the interventional device.

Therefore, there remains a need for new devices to safely andeffectively advance catheters to locations of interest in a morecontrolled manner to resolve these and other problems of the art.

SUMMARY

This invention facilitates the tracking and selection of branch vessels,as well as provide the means for stiffening the catheter body across thetortuosity to anchor the catheter and minimize the potential for thecatheter backing out of position while delivering interventional devicesto the distal anatomy.

The catheter consists of a torqueable shaft with a flexible distal end.The flexible distal end can be configured to be flexible in onedirection and stiffer in the opposite direction. The flexibility of thedistal end governed by a feature in the distal assembly designed tofacilitate bending in one direction, while resisting bending in theopposite direction. The feature comprising a laser cut tubular elementconfigured to flex preferentially in one direction while opposingflexure in the opposite direction. The tubular element is encapsulated(fused) between layers of flexible polymer.

The hub of the catheter is labeled to indicate the direction offlexibility so that the user can more easily steer the catheter throughthe vasculature. If the user approaches a bifurcation and desires totrack down the vessel rather than in the direction of the bifurcatedvessel, the user torques the shaft such that the flexible direction ofthe distal element is away from the bifurcation, thus facilitatingtracking of the device away from the bifurcation. If the user desires totrack in the direction of the bifurcation, the user will then torque theshaft such that the flexible direction of the distal element is in thedirection of the bifurcation, thus facilitating access to the bifurcatedvessel. To access through tortuosity and prevent the catheter frombacking out of position, the user first aligns the flexible segment toaccess through tortuosity as described above. Once the catheter hascrossed the tortuous segment, the user torques the catheter such thatthe flexible segment reverts inside of the dominant curve and the lessflexible segment stiffens inside the curve. This results in the catheterlocking itself in the curve and resisting backwards movement asinterventional devices are tracked through its lumen.

Disclosed herein are various exemplary devices for a steerable catheteror steerable locking catheter that can address tracking of catheterthrough tortuous anatomy and other problems of the art.

The devices can generally include a proximal hub, a proximal shaft, anintermediate shaft, and a flexible distal shaft. The flexible distalshaft having a proximal end and a distal end. The intermediate shafthaving a proximal end and a distal end wherein the distal end of theintermediate shaft is connected to the proximal end of the flexibledistal shaft. The proximal shaft having a proximal end and a distal end,wherein the distal end of the proximal shaft is connected to theproximal end of the intermediate shaft. The proximal hub comprising aproximal end and a distal end, wherein the distal end of the proximalhub is connected to the proximal end of the proximal shaft.

The devices can also generally include a flexible distal shaft that hasa first direction of flexibility and a second direction of flexibilityopposite to the first direction of flexibility. The flexible distalshaft can be torqued such that the first direction of flexibility is inthe direction of the desired direction of travel, thus facilitatingaccess to the bifurcation of the vasculature or a desired vessel. Thedevices can also generally include three layers, an inner layer, asegmented mid-layer with a plurality of notches, and an outer layer. Thesegmented mid-layer's notches have a depth and an outer depth and aninner width which relates to the angle of flexibility and enables theflexible distal shaft to bend in the first direction of flexibility.

An example device for a steerable catheter can include notches whereinthe outer width is greater than the inner width. The greater outer widthenables the flexible distal shaft to have greater flexibility in thefirst direction of flexibility. Another example device for a steerablecatheter can include notches that are different depths and widths. Thefirst depth and second depth of the notches can be selected to provideincreased, decreased, or the same flexibility as notches having the samedepth. The first depth and second depth can be selected to providecustomization to the flexibility enabling increased or decreasedflexibility at a specific point or points or location or locations onthe flexible distal shaft. The first outer width and second outer widthcan be selected to provide increased, decreased, or the same flexibilityas notches having the same outer width. The first outer width and secondouter width depth can be selected to provide customization to theflexibility enabling increased or decreased flexibility at a specificpoint or points or location or locations on the flexible distal shaft.

The first inner width and second inner width can be selected to provideincreased, decreased, or the same flexibility as notches having the sameinner width. The first inner width and second inner width depth can beselected to provide customization to the flexibility enabling increasedor decreased flexibility at a specific point or points or location orlocations on the flexible distal shaft.

Another example device for a steerable catheter can include notches of afirst geometric shape. The notch's geometric shape can be selected toprovide a variety of flexibility including increased flexibility ordecreased flexibility. The notch's geometric shape can be selected toprovide customization to the flexibility enabling increased or decreasedflexibility at a specific point or points or location or locations onthe flexible distal shaft.

Another example for a steerable catheter can include notches of twogeometric shapes wherein there is at least one notch with a firstgeometric shape and at least one notch with a second geometric shape.

The two geometric shapes can be selected to provide a variety offlexibility including increased or decreased flexibility. The twogeometric shapes can be selected to provide customization to theflexibility enabling increased or decreased flexibility at a specificpoint or points or location or locations on the flexible distal shaft.

Another example a steerable catheter can include a notch or notches in anumber of different orientations. The different orientations of thenotches can be selected to provide a variety of flexibility includingincreased or decreased flexibility. The different orientations of thenotches can be selected to provide customization to the flexibilityenabling increased or decreased flexibility at a specific point orpoints or location or locations on the flexible distal shaft.

Another example for a steerable catheter can include a segmentedmid-layer. The segmented mid-layer can have notches. The notches have adepth and an outer and an inner width that relate to the first angle offlexibility and enables the flexible distal shaft to bend in the firstdirection of flexibility. Additionally, the notches have a depth and anouter and an inner width that relate to the second angle of flexibilitythat is opposite that of the first angle of flexibility. The segmentedmid-layer and notches can be configured to resist bending the seconddirection of flexibility.

Another example for a steerable catheter can include an outer layer. Theouter layer can be made from a variety of materials suitable for acatheter including an elastic material. The outer layer can also includea radiopaque element to facilitate the identification of the firstdirection of flexibility. The outer layer can also include a radiopaqueelement to facilitate the identification of the second direction offlexibility. The outer layer can also include a radiopaque element tofacilitate the identification of the first direction of flexibility.

Another example for a steerable catheter can include the proximal shafthaving a proximal shaft flexibility and the intermediate shaft having anintermediate shaft flexibility. The flexibility of the flexible distalshaft can be greater than, less than, or equal to the intermediate shaftflexibility. The flexibility of the flexible distal shaft can be greaterthan, less than, or equal to the proximal shaft flexibility. Theflexibility of the intermediate shaft can be greater than, less than, orequal to the proximal shaft flexibility. Additionally, the flexibilityof the proximal shaft can be greater than, less than, or equal to theproximal shaft flexibility.

Another example for a steerable catheter can include the proximal hubhaving a label to indicate the first direction of flexibility of thesteerable catheter. The proximal hub can also have a label to indicatethe second direction of flexibility of the steerable catheter.

An example method of steering a steerable catheter can include aflexible distal shaft with a first direction of flexibility, a segmentedmid-layer with a plurality of notches having a depth, an outer width,and an inner width, rotating the steerable catheter, orienting theflexible distal shaft such that the first direction of flexibilityfacilitates travel in a desired direction of travel, advancing thesteerable catheter in the desired direction of travel.

The method can include notches where the outer width is greater than theinner width. The method can include notches where the plurality ofnotches is configured to bend in the first direction of flexibility. Themethod can include a flexible distal shaft with a second direction offlexibility. The method can include a flexible distal shaft with asecond direction of flexibility opposite to the first direction offlexibility. The method can include a flexible distal shaft where theflexibility of the flexible distal shaft is greater in the firstdirection of flexibility than any other direction.

An example method of locking a steerable catheter can include a flexibledistal shaft with a first direction of flexibility, a segmentedmid-layer with a plurality of notches having a depth, an outer width,and an inner width, rotating the steerable catheter, orienting theflexible distal shaft such that the first direction of flexibilityfacilitates travel in a desired direction of travel, advancing thesteerable catheter in the desired direction of travel.

The method of locking a steerable catheter can include notches where theouter width is greater than the inner width. The method can includenotches where the plurality of notches is configured to bend in thefirst direction of flexibility. The method can include a flexible distalshaft with a second direction of flexibility. The method can include aflexible distal shaft with a second direction of flexibility opposite tothe first direction of flexibility. The method can include a flexibledistal shaft where the flexibility of the flexible distal shaft isgreater in the first direction of flexibility than any other direction.

The method of locking a steerable catheter can include locking theflexible distal shaft in place by rotating the steerable catheter toorient the first direction of flexibility such that the flexible distalshaft contacts a wall of vessel branch to limit movement of the flexibledistal shaft in the desired direction of travel.

The method of locking a steerable catheter can include locking theflexible distal shaft in place by rotating the steerable catheter toorient the first direction of flexibility and second direction offlexibility such that the flexible distal shaft contacts a wall ofvessel branch to limit movement of the flexible distal shaft in thedesired direction of travel.

An example of a steerable catheter can include different orientations ofnotches to provide for a first primary direction of flexibility, asecond primary direction of flexibility, a first secondary direction offlexibility, and a second secondary direction of flexibility. Where thefirst primary direction of flexibility is not in the same direction ofthe second primary direction of flexibility. Where the first secondarydirection of flexibility is not the same direction of the secondsecondary direction of flexibility.

The example can include an inner layer, a segmented mid-layer withdifferent oriented notches, and an outer layer. The example can includea segmented mid-layer with a primary plurality of notches with a primarydepth, a primary outer width, and a primary inner width. The example caninclude a segmented mid-layer where the primary depth, the primary outerwidth, and the primary inner width are related to the primary angle offlexibility. The example can include a segmented mid-layer where theprimary outer width is greater than the primary inner width. The examplecan include a segmented mid-layer where the primary plurality of notchesis configured to bend in the first primary direction of flexibility.

The example can include a secondary plurality of notches with asecondary depth, a secondary outer width, and a secondary inner width.The example can include a secondary plurality of notches where thesecondary depth, the secondary outer width, and the secondary innerwidth are related to the secondary angle of flexibility. The example caninclude a secondary plurality of notches where the secondary outer widthis greater than the secondary inner width. The example can include asecondary plurality of notches where the secondary plurality of notchesis configured to bend in the first secondary direction of flexibility.

Another example of the steerable catheter can include a label toindicate the first primary direction of flexibility. The example caninclude a label to indicate the first secondary direction offlexibility. Another example for a steerable catheter can include anouter layer. The outer layer can be made from a variety of materialssuitable for a catheter including an elastic material. The outer layercan also include a radiopaque element to facilitate the identificationof the first primary direction of flexibility. The outer layer can alsoinclude a radiopaque element to facilitate the identification of thesecond primary direction of flexibility. The outer layer can alsoinclude a radiopaque element to facilitate the identification of thefirst secondary direction of flexibility. The outer layer can alsoinclude a radiopaque element to facilitate the identification of thesecond secondary direction of flexibility.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further aspects of this invention are further discussedwith reference to the following description in conjunction with theaccompanying drawings, in which like numerals indicate like structuralelements and features in various figures. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingprinciples of the invention. The figures depict one or moreimplementations of the inventive devices, by way of example only, not byway of limitation.

FIG. 1A is a side view illustration of the steerable locking catheter ofthe present invention.

FIG. 1B a cross-sectional view illustration of the notches located atthe distal end of the present invention shown in FIG. 1A.

FIGS. 1C to 1E are illustrations of the notches of the presentinvention.

FIGS. 2A to 2B are side view illustrations of the directions offlexibility of the present invention.

FIG. 3 is a side view illustration of the flexible distal shaft flexedin the first direction of flexibility.

FIGS. 4A to 4B are side view illustrations of the method of steering asteerable catheter to orient the first direction of flexibility in thedesired direction of travel.

FIGS. 5A to 5B are side view illustrations of the steerable catheterlocated within the desired vessel branch and the orientation of thefirst direction of flexibility.

FIGS. 6A to 6B are side view illustrations of the method of locking asteerable catheter to orient the first direction of flexibility suchthat the flexible distal shaft contacts a wall of the vessel branch tolimit movement of the flexible distal shaft.

FIG. 7A is a side view illustration of the steerable locking catheterwith notches having two different orientations of the present invention.

FIGS. 7B to 7E are side view illustrations of the notches with differentorientations located at the distal end of the present invention shown inFIG. 7A.

FIGS. 8A to 8C are side view illustrations of the steerable catheterwith notches with different orientations located within the desirevessel branch.

FIG. 9 is an illustration of an exemplary steering sequence of theexemplary device according to aspects of the present invention.

FIG. 10 is an illustration of an exemplary locking sequence of theexemplary device according to aspects of the present invention.

DETAILED DESCRIPTION

FIG. 1A illustrates a side view of the steerable catheter. Asillustrated, the steerable catheter 100 can have a proximal hub 200, aproximal shaft 300, an intermediate shaft 400, and a flexible distalshaft. The proximal hub 200 can have a proximal end 250 and a distal end260. The proximal hub 200 can have a label 202. The proximal shaft 300can have a proximal end 350 and a distal end 360. The intermediate shaft400 can have a proximal end 450 and a distal end 460. The flexibledistal shaft can have a proximal end 550 and a distal end 560. Thedistal end 260 of the proximal hub 200 can be connected to the proximalend 350 of the proximal shaft 300. The distal end 360 of the proximalshaft 300 can be connected to the proximal end 450 of the intermediateshaft 400. The distal end 460 of the intermediate shaft 400 can beconnected to the proximal end 550 of the flexible distal shaft. Thesteerable catheter 100 can have a first direction of flexibility 102.The steerable catheter 100 can have a second direction of flexibility104. The first direction of flexibility 102 can be opposite to that ofthe second direction of flexibility 104.

The proximal shaft 300 can have a proximal shaft flexibility and theintermediate shaft 400 can have an intermediate shaft flexibility. Theflexibility of the intermediate shaft 400 can be greater than theproximal shaft flexibility and the flexibility of the flexible distalshaft 500 is greater than both the intermediate shaft and proximal shaftflexibility. This varying stiffness, or flexibility, along the length ofthe steerable catheter 100 allows for an easier transfer of torque fromthe proximal hub 200 to the flexible distal shaft 500. This permits theuser to apply torque to the proximal hub 200 to easily orientate theflexible distal shaft 500 in the needed radial direction to utilize theeither the first or second direction of flexibility 102, 104 to advancethe catheter through the vasculature. Note that certain catheters 100can be advanced from a patient's inner thigh, over the cardiac arch, andup into the neurovascular inside the patient's skull and thus thedistance and tortuosity can be significant.

The changes in flexibility between the proximal shaft and theintermediate shaft can be from using different materials for eachportion of the shaft, each portion being of a different stiffness ordurometer. Alternately, the proximal and intermediate shafts can be madeof the same material and additional layers or additives can be providedin the shafts to control the individual stiffness. These examples can becombined to provide the needed flexibility and/or stiffness. Note thateach of the proximal shaft 300 and the intermediate shaft 400 can haveuniform stiffness across their length, or it can vary. As an example,the stiffness of the proximal shaft 300 can decrease from the proximalend 350 to the distal end 360, so the stiffness of the distal end 360matches the stiffness of the proximal end 450 of the intermediate shaft400. This gradual transition of stiffness, in certain examples, canprevent localized stiffness “transition points”.

FIG. 1B illustrates a cross-section of the steerable catheter depictedin FIG. 1A. As illustrated, the steerable catheter 100 can have an innerlayer 502, a segmented mid-layer 504, and an outer layer 506. Thesegmented mid-layer 504 can have notches 600 as depicted in FIGS. 1C,1D, and 1E. The segmented mid-layer 504 and the size and shape of thenotches 600 can relate to the first direction of flexibility 102. Thesegmented mid-layer 504 and the size and shape of the notches 600 canrelate to the second direction of flexibility 104. As with all catheters100, there is an inner lumen 108 passing along the inside the catheter100 to permit the delivery of surgical tools or implements or providepassage for the removal of clots, tissue, or fluid from the patient.

FIGS. 1C, 1D, and 1E illustrate the variety of notches. The notch 600 islocated within the segmented mid-layer 504. The notch 600 can have adepth 602, 602A, or 602B. The notch can have an outer width 604, 604A,or 604B. The notch can have an inner width 606, 606A, or 606B. FIG. 1Cdepicts a uniformly sized notch 600 wherein the plurality of notches canhave the same depth 602, outer width 604, and inner width 606. FIGS. 1Dand 1E depict two different sized notches wherein the first depth 602Acan be different than the second depth 602B. The first outer width 604Acan be different than the second outer width 604B. The first inner width606A can be different than the second inner width 606B.

The depth 602, outer width 604, and inner width 606 can relate to theflexibility in the first direction of flexibility 102. The depth 602,outer width 604, and inner width 606 can relate to the flexibility inthe second direction of flexibility 104. The first depth 602A, firstouter width 604A, and first inner width 606A can relate to theflexibility in the first direction of flexibility 102. The first depth602A, first outer width 604A, and first inner width 606A can relate tothe flexibility in the second direction of flexibility 104. The seconddepth 602B, second outer width 604B, and second inner width 606B canrelate to the flexibility in the first direction of flexibility 102. Thesecond depth 602B, second outer width 604B, and second inner width 606Bcan relate to the flexibility in the second direction of flexibility104.

In examples, the first direction of flexibility 102 of the steerablecatheter 100 can provide more flexibility than the second direction offlexibility 104. In one example, the first direction of flexibility 102can be provided by closing the notch 600 while the second direction offlexibility 104 can be provided by opening the notch 600. The closing ofthe notch 600 can be provided by causing the sides defined by the outerwidth (604, 604A, or 604B) of the notch 600 to touch or at least becloser to one another than when not flexed. Alternatively, the closingof the notch 600 can be provided by reducing the angle of flexibility106 in comparison to when the notch 600 is not flexed. The opening ofthe notch 600 can be provided by causing the sides defined by the outerwidth (604, 604A, or 604B) of the notch 600 to at least be further toone another than when not flexed. Alternatively, the opening of thenotch 600 can be provided by increasing the angle of flexibility 106 incomparison to when the notch 600 is not flexed. Alternately, thedifferent flexibility in the first and second directions of flexibility102, 104, can come from different shaped notches 600, as above. Thevariations in flexibility can translate to the amount of deflection ofthe distal end 560 of the flexible distal shaft 500.

FIGS. 2A and 2B illustrate side views of the steerable catheter, thepotential flexibility within the first direction of flexibility and thesecond direction of flexibility, and the method of steering a steerablecatheter. The flexible distal shaft 500 can have increased flexibilityin the first direction of flexibility 102. The flexible distal shaft 500can have decreased flexibility in the second direction of flexibility104. The method of steering a steerable catheter 700 enables therotating of the steerable catheter 100 to alter the first direction offlexibility 102 and second direction of flexibility 104 depending on thepreferred orientation. In one example, the label 202 can provideguidance to the user as to which radial direction corresponds to the oneor more directions of flexibility 102, 104. As the user advances thecatheter 100, rotating the proximal hub 200 can orient the flexibledistal shaft 500 toward the chosen direction to advance into aparticular fork or branch of the vasculature or desired direction oftravel.

In addition, one of the layers 502, 504, 506, 510 can include aradiopaque element to facilitate the identification of the firstdirection of flexibility 102 and/or the second direction of flexibility104 or the first primary direction of flexibility 140, the secondprimary direction of flexibility 142 or the first secondary direction offlexibility 150 and the second secondary direction of flexibility 152.In one example, the outer layer 506 has the radiopaque element.

FIG. 3 illustrates a side view of the steerable catheter flexed in thefirst direction of flexibility illustrating the ability to orient thesteerable catheter in the desired direction of travel. The flexibledistal shaft 500 can be flexed at a number of angles, including thedepicted orthogonal angle, in the first direction of flexibility 102.The flexible distal shaft 500 can be flexed to facilitate the steerablecatheter 100 to advance in the desired direction of travel 110. In oneexample, the first direction of flexibility 102 can be provided byclosing a subset of the notches 600 while the second direction offlexibility 104 can be provided by opening a subset of notches 600. Theclosing of a subset of the notches 600 can be provided by causing thesides defined by the outer width (604, 604A, or 604B) of a specificnotch 600 to touch or at least be closer to one another than when notflexed. Alternatively, the closing of the notch 600 can be provided byreducing the angle of flexibility 106 in comparison to when the notch600 is not flexed. The opening of a subset of the notches 600 can beprovided by causing the sides defined by the outer width (604, 604A, or604B) of a specific notch 600 to at least be further to one another thanwhen not flexed. Alternatively, the opening of the notch 600 can beprovided by increasing the angle of flexibility 106 in comparison towhen the notch 600 is not flexed.

FIGS. 4A and 4B illustrate a side view of the method of steering thesteerable catheter into a desired vessel branch. The steerable catheter100 can be located in a primary vessel 130 with a first direction offlexibility 102 oriented perpendicular to the desired direction oftravel 110. The steerable catheter 100 can be rotated by the method ofsteering a steerable catheter 700 to orient the first direction offlexibility 102 in the direction of the desired vessel branch 120. Thesteerable catheter 100 can be advanced in the desired direction oftravel 110 such that the first direction of flexibility 102 enables thesteerable catheter 100 to more easily advance into the desired vesselbranch 120.

FIGS. 5A and 5B illustrate the notches of the flexible distal shaft andtheir orientation when flexed in the direction of the first direction offlexibility. The flexible distal shaft 500 can have the first directionof flexibility 102 oriented in the direction of the desired vesselbranch 120. FIG. 5B depicts a close-up of the flexible distal shaft andthe notches. The notches 600 can be oriented in the first direction offlexibility 102. The notches 600 can form an angle of flexibility 106.The notches 600 can determine the flexibility of the steerable catheter100 in the direction of the first direction of flexibility 102.

FIGS. 6A and 6B illustrate a side view of the method of locking asteerable catheter. The method of locking a steerable catheter 800 caninclude rotating a flexible distal shaft 500 at the proximal hub 200 toorient the first direction of flexibility 102 such that the flexibledistal shaft 500 contacts a wall of the vessel branch 122 to limit themovement of the flexible distal shaft 500 in the desired direction oftravel 110. FIG. 6B depicts a close-up side view of the notches andtheir orientation with respect to the vessel branches. The method oflocking a steerable catheter 800 can include rotating a flexible distalshaft 500 at the proximal hub 200 orienting the notches 600 which areoriented in the same direction as the first direction of flexibility102.

An example of locking can be entering the desired branch vessel 120using the first direction of flexibility 102 to bend the distal flexibleshaft 500 to “make the turn” into the branch. This is illustrated inFIGS. 5A and 5B and as illustrated the first direction of flexibility102 is directed to the “inside” of the curve. The user then torques orrotates the catheter 100 so that the first direction of flexibility 102is opposed to the “inside,” as illustrated in FIGS. 6A and 6B. Thedistal flexible shaft 500 is now more “stiff” as the second direction offlexibility 104 faces the “inside” of the curve. Less flexibility cantranslate to the distal end 560 of the distal shaft 500 not being ableto make the turn as “sharp” as if it was more flexible. This now movesthe flexible distal shaft 500 to contact the “outside” wall of thevessel, “locking” the catheter 100 into place. Locking the catheter 100can be beneficial during certain procedures to allow for retrieval ordeployment of elements in and out of the lumen 108.

FIG. 7A illustrates a side view of a steerable catheter with notcheswith two different orientations. The steerable catheter 100 can includenotches with multiple, different orientations. For example, one set ofnotches is oriented in the direction of the first primary direction offlexibility 140 and the second primary direction of flexibility 142. Oneset of notches is oriented in the direction of the first secondarydirection of flexibility 150 and the second secondary direction offlexibility 152.

FIGS. 7B and 7C illustrate cross-section views of the steerable catheteras depicted in FIG. 7. The steerable catheter 100 can have an innerlayer 502, a segmented mid-layer with different oriented notches 510,and an outer layer 506. FIG. 7B illustrates the segmented mid-layer withdifferent oriented notches 510 can have a primary notch 610 oriented toenable flexibility in the first primary direction of flexibility 140.FIG. 7C illustrates the segmented mid-layer with different orientednotches 510 can have a secondary notch 620 oriented to enableflexibility in the first secondary direction of flexibility 150.

FIG. 7D illustrates the primary notch 610 in the segmented mid-layer510. For example, the primary notch 610 having a depth 612, an outerwidth 614 and an inner width 616. The depth 612, outer width 614, andinner width 616 can relate to the flexibility in the first primarydirection of flexibility 140. The depth 612, outer width 614, and innerwidth 616 can relate to the flexibility in the second primary directionof flexibility 142.

FIG. 7E illustrates the secondary notch 620 in the segmented mid-layer510. For example, the secondary notch 620 having a depth 622, an outerwidth 624, and an inner width 624. The depth 622, outer width 624, andinner width 626 can relate to the flexibility in the first secondarydirection of flexibility 150. The depth 622, outer width 624, and innerwidth 626 can relate to the flexibility in the second secondarydirection of flexibility 152.

FIG. 8A illustrates a side view of the steerable catheter with notcheswith two different orientations. The steerable catheter 100 can have asegmented mid-layer with different oriented notches 510 such that thesteerable catheter 100 has flexibility in the first primary direction offlexibility 140 and the first secondary direction of flexibility 150.FIGS. 8B and 8C depict close-up side views of the primary and secondarynotches and their orientation with respect to the first and secondprimary directions of flexibility. The steerable catheter 100 can have aprimary notch 610 enabling flexibility in the first primary direction offlexibility 140 and a primary angle of flexibility 144. The steerablecatheter 100 can have a secondary notch 620 enabling flexibility in thesecond primary direction of flexibility 150 and a secondary angle offlexibility 154.

In examples, the first primary direction of flexibility 140 can beprovided by closing a subset of the primary notches 610 while the secondprimary direction of flexibility 142 can be provided by opening a subsetof the primary notches 610. The closing of a subset of the primarynotches 610 can be provided by causing the sides defined by the outerwidth 614 of a specific primary notch 610 to touch or at least be closerto one another than when not flexed. Alternatively, the closing of aprimary notch 610 can be provided by reducing the primary angle offlexibility 144 in comparison to when the primary notch 610 is notflexed. The opening of a subset of the primary notches 610 can beprovided by causing the sides defined by the outer width 614 of aspecific primary notch 610 to at least be further to one another thanwhen not flexed. Alternatively, the opening of the primary notch 610 canbe provided by increasing the primary angle of flexibility 144 incomparison to when the primary notch 610 is not flexed.

In examples, the second primary direction of flexibility 150 can beprovided by closing a subset of the secondary notches 620 while thesecond secondary direction of flexibility 152 can be provided by openinga subset of the secondary notches 620. The closing of a subset of thesecondary notches 620 can be provided by causing the sides defined bythe outer width 624 of a specific secondary notch 620 to touch or atleast be closer to one another than when not flexed. Alternatively, theclosing of a secondary notch 620 can be provided by reducing thesecondary angle of flexibility 154 in comparison to when the secondarynotch 620 is not flexed. The opening of a subset of the secondarynotches 620 can be provided by causing the sides defined by the outerwidth 624 of a specific secondary notch 620 to at least be further toone another than when not flexed. Alternatively, the opening of thesecondary notch 620 can be provided by increasing the secondary angle offlexibility 154 in comparison to when the secondary notch 620 is notflexed.

FIG. 9 is a flow diagram outlining example method steps that can becarried out to steer a steerable catheter. The method steps can beimplemented by any of the example means described herein or by any meansthat would be known to one of ordinary skill in the art.

Referring to a method 700 outlined in FIG. 9, in step 710 a steerablecatheter 100 can be provided. In step 720, the steerable catheter 100can be rotated. In step 730, the flexible distal shaft 500 of thesteerable catheter 100 can be oriented in the preferred direction. Instep 740, the steerable catheter 100 can be advanced in the desireddirection of travel 110 benefitting from the orientation of the flexibledistal shaft 500 and its first direction of flexibility 102.

FIG. 10 is a flow diagram outlining example method steps that can becarried out to lock a steerable catheter. The method steps can beimplemented by any of the example means described herein or by any meansthat would be known to one of ordinary skill in the art.

Referring to a method 800 outlined in FIG. 10, in step 810 a steerablecatheter 100 can be provided. In step 820, the steerable catheter 100can be rotated. In step 830, the flexible distal shaft 500 of thesteerable catheter 100 can be oriented in the preferred direction. Instep 840, the steerable catheter 100 can be advanced in the desireddirection of travel 110 benefitting from the orientation of the flexibledistal shaft 500 and its first direction of flexibility 102. In step850, the steerable catheter 100 can be rotated pursuant to the method ofsteering a steerable catheter 700 to orient the flexible distal shaft500 first direction of flexibility 102 such that the flexible distalshaft 500 contacts a wall of vessel branch 122 to limit movement of theflexible distal shaft in the desired direction of travel 110.

The descriptions contained herein are examples of embodiments of theinvention and are not intended in any way to limit the scope of theinvention. As described herein, the invention contemplates manyvariations and modifications of the . . . device, including . . . .These modifications would be apparent to those having ordinary skill inthe art to which this invention relates and are intended to be withinthe scope of the claims which follow.

1. A steerable catheter comprising: a flexible distal shaft comprising:a proximal end; a distal end; a first direction of flexibility; a seconddirection of flexibility opposite to the first direction of flexibility;an inner layer; a segmented mid-layer comprising a plurality of notchescomprising a depth, an outer width, and an inner width; wherein thedepth, the outer width, and the inner width are related to an angle offlexibility; and wherein the outer width is greater than the innerwidth; and wherein the plurality of notches are configured to bend inthe first direction of flexibility; and an outer layer; wherein aflexibility of the flexible distal shaft is greater in the firstdirection of flexibility than any other direction.
 2. The steerablecatheter of claim 1, wherein the plurality of notches are a firstgeometric shape.
 3. The steerable catheter of claim 2, wherein a subsetof the plurality of the notches comprise at least one of a secondgeometric shape.
 4. The steerable catheter of claim 1, wherein a subsetof the plurality of the notches comprise at least one of a first depth,a first outer width, a first inner width, a second depth, a second outerwidth, and a second inner width.
 5. The steerable catheter of claim 1,wherein the segmented mid-layer is configured to resist bending in thesecond direction of flexibility.
 6. The steerable catheter of claim 1,wherein the outer layer is elastic.
 7. The steerable catheter of claim1, further comprising: an intermediate shaft comprising a proximal endand a distal end wherein the distal end of the intermediate shaft isconnected to the proximal end of the flexible distal shaft; a proximalshaft comprising a proximal end and a distal end, wherein the distal endof the proximal shaft is connected to the proximal end of theintermediate shaft; and a proximal hub comprising a proximal end and adistal end, wherein the distal end of the proximal hub is connected tothe proximal end of the proximal shaft.
 8. The steerable catheter ofclaim 7, further comprising: wherein the proximal shaft comprising aproximal shaft flexibility; wherein the intermediate shaft comprising anintermediate shaft flexibility; wherein the flexibility of the flexibledistal shaft is greater than the intermediate shaft flexibility; whereinthe flexibility of the flexible distal shaft is greater than theproximal shaft flexibility; wherein the flexibility of the intermediateshaft is greater than the proximal shaft flexibility; and wherein achange in flexibility from the proximal shaft flexibility to theintermediate shaft flexibility to the flexibility of the flexible distalshaft allows a torque to be transmitted along a length of the catheter.9. The steerable catheter of claim 7, wherein the proximal hub comprisesa label to indicate the first direction of flexibility of the steerablecatheter.
 10. The steerable catheter of claim 1, wherein the outer layercomprises a radiopaque element to determine the first direction offlexibility.
 11. A method of steering a steerable catheter, the methodcomprising: providing a steerable catheter comprising a flexible distalshaft comprising a first direction of flexibility, and a segmentedmid-layer comprising a plurality of notches comprising a depth, an outerwidth, and an inner width, wherein the outer width is greater than theinner width, wherein the plurality of notches are configured to bend inthe first direction of flexibility; rotating the steerable catheter;orienting the flexible distal shaft such that the first direction offlexibility facilitates travel in a desired direction of travel; andadvancing the steerable catheter in the desired direction of travel. 12.The method of steering a steerable catheter of claim 11, the methodfurther comprising: providing a steerable catheter comprising a seconddirection of flexibility opposite to the first direction of flexibility.13. The method of steering a steerable catheter of claim 11, the methodfurther comprising: providing a steerable catheter wherein a flexibilityof the flexible distal shaft is greater in the first direction offlexibility than any other direction.
 14. The method of claim 11, themethod of locking a steerable catheter further comprising: locking theflexible distal shaft in place by rotating the steerable catheter toorient the first direction of flexibility such that the flexible distalshaft contacts a wall of vessel branch to limit movement of the flexibledistal shaft in the desired direction of travel.
 15. The method of claim14, the method of locking a steerable catheter further comprising:locking the flexible distal shaft in place by rotating the steerablecatheter to orient the first direction of flexibility and seconddirection of flexibility such that the flexible distal shaft contacts awall of vessel branch to limit movement of the flexible distal shaft inthe desired direction of travel.
 16. A steerable catheter comprising: aflexible distal shaft comprising: a first primary direction offlexibility; a second primary direction of flexibility; a firstsecondary direction of flexibility; a second secondary direction offlexibility; an inner layer; a segmented mid-layer with differentoriented notches comprising: a primary plurality of notches comprising aprimary depth, a primary outer width, and a primary inner width; andwherein the primary depth, the primary outer width, and the primaryinner width are related to the primary angle of flexibility; wherein theprimary outer width is greater than the primary inner width; wherein theprimary plurality of notches are configured to bend in the first primarydirection of flexibility; a secondary plurality of notches comprising asecondary depth, a secondary outer width, and a secondary inner width;wherein the secondary depth, the secondary outer width, and thesecondary inner width are related to the secondary angle of flexibility;the secondary outer width is greater than the secondary inner width; andwherein the secondary plurality of notches are configured to bend in thefirst secondary direction of flexibility; and an outer layer.
 17. Thesteerable catheter of claim 16, wherein the proximal hub comprising alabel to indicate the first primary direction of flexibility and thefirst secondary direction of flexibility.
 18. The steerable catheter ofclaim 16, wherein the outer layer is elastic.
 19. The steerable catheterof claim 16, wherein the outer layer comprises a radiopaque element todetermine the first primary direction of flexibility.
 20. The steerablecatheter of claim 16, wherein the outer layer comprises a radiopaqueelement to determine the first secondary direction of flexibility.